Tuning and coupling device for a frequency-modulation tube with a delay line operating as a line resonator



Aug. 25, 1970 GROSS 525,955

TU ND COUPLING DEVICE FOR A FREQUENCY-MODUL ION 7 TU TH A D Y LINE OPERATING AS A LINE RESON R Filed July 5, 1967 Fig.1

r L, 10 E1, 6 h T 1 INVENTOR FRANZ GROSS BY ATTY'S United States Patent US. Cl. 333-98 2 Claims ABSTRACT OF THE DISCLOSURE A tuning and coupling device for a frequency-modulation tube with a delay line operating as a line resonator, in which the coupling means comprises a tuning slide at least partially of a ferromagnetic material disposed in a tubular coupling conductor of non-magnetic material, which slide is magnetically coupled to a magnet arrangement exteriorly of the tubular conductor and movable therealong as such arrangement is moved along the exterior of the conductor, the slide also being provided with slits therein for the passage of high frequency, the size of which is adjustable by varying the position of a movable disk carried by the slide, such disk being provided with ferromagnetic parts cooperable with further magnetic means disposed exteriorly of the tubular conductor, whereby movement of the latter means is operative to adjustably move such disk.

The invention relates to a tuning and coupling device for a frequency-modulation tube for producing or amplifying extremely high frequencies with an electron gun at one end and an electron catcher at the other end of the tube, as well as at least one delay line operating as a line resonator arranged therebetween, which, through a following vacuum-tight coupling window, is closely coupled to a coupling conductor containing a movable tuning slide.

Such a frequency-modulation tube is known from German Pat. 1,121,231, in which patent a tube for producing extremely high frequencies is involved and wherein the delay line is connected at the side of the catcher in the direction of the electron beam, with a waveguide tube containing a decoupling slide by means of a vacuumtight waveguide intermediate piece. To couple the high frequency energy produced, an interaction gap is provided between the tuning slide and the wall of the coupling waveguide tube.

A frequency-modulation tube along the lines of the German patent referred to presents, as a construction problem, the ditficulty to spatially accommodate a device to the move tuning slide without impairing the high frequency transfer from the tube to the load. This problem in a tuning and coupling device of the kind initially referred to is solved in the invention by the feature that the coupling conductor is non-magnetic, while the tuning slide consists mainly of ferromagnetic material and is magnetically coupled to a magnet arrangement which can be moved along the exterior of the coupling conductor.

A device according to the invention has, first of all, the advantage that in order to actuate the tuning slide, a mechanical control element disposed within the coupling out conductor is unnecessary. In particular, openings in the decoupling conductor which could interefere with the high frequency are eliminated. Furthermore, since an adjusting mechanism directly engaging in the tuning slide is avoided, it is possible in a very simple manner to provide the end of the coupling conductor with a rigid connecting plug for a load line.

3,525,955 Patented Aug. 25, 1970 The tuning slide of a device according to the invention is suitably slidably disposed in the coupling conductor, and in a further development of the invention the tuning slide is mounted in the coupling conductor, which preferably can be a coaxial line, by means of ring or pinshaped members of dielectric material. Consequently, besides a reduction in mechanical friction, there is the considerable advantage of a contact-free guidance of the tuning slide in the coupling conductor, as a result of which any uncertainty in the reproducibility of the slide adjusment, due to metallic wear, is avoided and electrical losses arising from transfer resistance are eliminated. The contact-free guidance of the tuning slide in a coaxial coupling line can be achieved by constructing the tuning slide as a cylindrical part which occupies the space between the outer and inner conductors of the coaxial line with the slide having a small clearance with respect to the inner conductor and being supported, at least with respect to the outer conductor, by dielectric guide members. In this connection, the guide members preferably should be symmetrically disposed about the periphery of the cylindrical part, for example, in three longituidnally extending rows of two guide members each, in the form of pins of ceramic or synthetic material, and can advantageously be so inserted in the cylindrical part that the metallic tuning slide is completely supported and guided by dielectric means to insure the elimination of direct contact with the inner conductor, as well as with the outer conductor of the coaxial line. Rings of ceramic or synthetic material also are suitable for the same purpose, which can be inserted either in the walls of the tuning slide or placed on its face in the form of disks.

In a tuning and coupling device according to the invention, the high-frequency energy, as is known in the prior art, can be coupled out through a gap provided between the tuning slide and the adjacent Wall parts of the coupling conductor. However, it is also possible and advantageous to construct the tuning slide as a hollow cylinder having a front wall which is provided with recesses. In order to be able to vary the high frequency coupling between the tube and a connected load in the operation of the device, it is proposed in a further development of the invention to rotatably mount a disk consisting of dielectric material in the tuning slide ahead of the front wall, which is provided with Windows, and having a metallic lining, which forms windows of the same form as those in the tuning slide. Ferromagnetic parts attached to this disk, for example, two silver coated iron strips or leaves, enable the disk to be rotatably moved with the aid of an additional magnet mounted on the magnet arrangement located outside the coupling conductor, whereby the metallic lining of the dielectric disk covers more or less of the Windows in the tuning slide and in this manner alters the coupling effected by the tuning slide. Thus, on the one hand, adjustment for each working frequency of the tube can be determined by the position of the tuning slide for the most favorable conditions for the oscillatory capacity of the line resonator of the tube, and on the other hand, the value of the high frequency to be coupled out of the device.

In the drawings, wherein like reference numerals indicate like or corresponding parts:

FIG. 1 is a longitudinal sectional view of a tuning and coupling device embodying the invention; and

FIG. 2 is a transverse sectional view of a modified form of tuning slide.

Referring to FIG. 1, a brass tube 1 is illustrated which is to be connected at the end appearing at the left side of the drawing to the end of the catcher electrode of a frequency-modulation tube (not shown) which contains a delay line (conduit resonator) reflectively terminated at both ends. In this connection, a close coupling of the delay line with tube 1, through a vacuum-tight window at the end of the tube, is assumed. A transversely extending cross portion 2 is provided on the conduit resonator for the high frequency matching of the equipment involved, whose one free end is bent back in the direction of the longitudinal axis of the tube 1, and subsequently merges into the inner conductor 3 of a coaxial line 4, whose outer conductor is formed by the tube 1. Disposed in the space between the inner conductor 3 and the tube 1 is a tuning slide 5 of magnetic material, particularly of steel, which is silver coated to provide good high frequency conductivity, and is supported in the coaxial line 4 with respect to the inner surface of the inner shell by three longitudinally extending insulating conical guide members 6, each row of which contains two guide members positioned one behind the other in the longitudinal direction of the tuning slide, with the rows being symmetrically circumferentially spaced. The guide members 6 may consist of the synthetic material polytetrafluorethyl available under the name Teflon or the synthetic material Tolitul based on polystyrol. Freedom from contact between the inner conductor 3 of the coaxial conduit and the tuning slide 5 is insured by a narrow annular space 7 which, for example, in some tenths of a millimeter in radial direction. It will be apparent, however, that dielectric guide members, similar to the members 6, also can be provided to good advantage between the inner conductor 3 and the tuning slide 5 to maintain the desired spacing.

The tuning slide 5, due to its magnetic properties, is slidable along the tube by means of a magnet arrangement, which can be moved along the outer surface of the tube 1. The illustrated magnet arrangement comprises a permanent ring magnet 8 which coaxially encircles the tube 1 and is disposed between two annular disk-shaped pole pieces 9 on the tube 1. Sliding of the pole pieces 9 on the tube 1, which usually is accomplished by means of a fine adjusting pinion and which is easily installed externally of the tube 1, magnetically carries the coupling slide therewith and thus renders possible the coupling of the conductor resonator of a tube provided with a device according to the invention.

In the illustrative embodiment of FIG. 1, the tuning slide 5 is not constructed as a solid mass but as a hollow cylinder having a front wall which faces a rigidly arranged high frequency connection plug 10 disposed at the right hand end of the tube 1. Such front wall is provided with coupling slits 11, through which a considerable part of the high frequency energy, which has been produced or amplified in a tube associated with the device according to the invention, is to exit. Directly behind the front wall with the coupling slits 11 is a dielectric disk 13, rotatably mounted on a small annular shoulder 12 of the tuning slide 5, comprising particularly synthetic material, which carries a metallic lining 14 having substantially the same form as that of the front wall of the coupling slide 5 provided with the coupling slits 11. Two circular silver coated iron leaves 15 are connected with the disk 13 in diametrically facing positions, with the aid of which the disk 13 can be magnetically rotated without direct contact. For this purpose, there is disposed on the magnet arrangement comprising the magnet 8 and the pole pieces 9, an additional magnet 16 which is movable in circumferential direction about the periphery of the tube 1. Through a rotation of the additional magnet 16 metallic lining 14 of the disk 13 may be moved to cover more or less the coupling slits 11, thereby varying the high frequency coupling of the device in accordance with the invention. This possibility of varying the high frequency coupling has the advantage that the optimal working condition of a connected tube operating with a conduit resonator can be attained for an arbitrary adjustment of the slide 5, when the most favorable high frequency coupling,

which requires a certain efiective width of the coupling 4 slit, depends in each case on the adjusted working frequency involved.

The most favorable conditions for the high frequency coupling can also be adjusted to srxecial advantage by a modified arrangement of that illustrated in FIG. 1 in which the tuning slide 5 is not hollow, but of solid construction, whereby the coupling out of the energy takes place through an annular clearance between the tuning slide 5 and the inner conductor 3 of the coaxial conduit. Furthermore, the inner conductor 3 and the inner bore hole of the slide 5 in the tube must be slightly eccentrically arranged. Thus, when the tuning slide 5 is rotated about its axis, the effective radial width of the coupling slit, and thereby its coupling effect, is altered. To achieve these results in a simple manner, the ring magnet 8 is radially magnetized and the tuning slide 5, in the longitudinal direction of the coaxial conduit 4, is only partially formed of magnetic material. A corresponding construction of the slide 5 is illustrated in FIG. 2. The tuning slide 5 contains two diametrically disposed iron ring pieces 17, between which lenticular pieces 1-8 of non-magnetic material, e.g. of brass, are suitably soldered. By notching the corresponding ring magnet 8 in circumferential direction of the periphery of the tube 1, the slide is likewise rotated and thus the coupling of energy is adjusted, whereas a displacement of the magnet in the longitudinal direction of the tube 1 provides adjustment of the coupled frequency.

The invention is not limited to the embodiments illustrated. In particular, the tuning slide does not necessarily have to be conducted in the coupling conductor free from contact, as long as this is not prescribed from the point of view of high frequency engineering. Furthermore, it is not necessary that the coupling conductor be a coaxial conduit. Finally, in the case where the high frequency coupled out is effected only through a gap between the tuning slide and the adjoining wall parts of the coupling conductor, and the tube in the entire range of its working frequency requires only a single mechanical tuning adjustment, the frequency dependency of the optimal width of the gap can be advantageously derived by means of a continuous change in the inner measurements of a coupling conductor along the length of the coupling adjustment, for example, a conical configuration.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

I claim:

1. A tuning and coupling device for a frequency-modulated tube for generating or amplifying millimeter waves with an electron beam generator at one end and an electron collector at the other end of the tube, and having at least one delay line located therebetween acting as a line resonator, closely coupled through a following vacuum-tight coupling window with a non-magnetic coupling conductor in the form of a coaxial line, said conductor containing a tuning slide displaceable in longitudinal direction of the coupling conductor, which is magnetically coupled to and movable with a magnetic system movable along the exterior of the coupling conductor, characterized in that the tuning slide is disposed between the outer and inner conductors of said coaxial line and constructed of a ferromagnetic material in the form of a hollow cylinder, with a frontal wall thereof having openings therein, a disk of dielectric material, having a metal layer thereon of substantially the same configuration as said frontal wall, said disk being longitudinally movable with said slide and rotatable relative thereto, and means, including an additional magnet adjacent said magnet system and cooperable elements movable with said disk for elifdecting rotary adjustment of said disk relative to said s 1 e.

2. A device according to claim 1, wherein the magnet arrangement is provided with an annular magnet coaxially enclosing the coupling conductor, said annular magnet being disposed between two annular disk-shaped pole 5 6 pieces which are movable along the outer surface of the FOREIGN PATENTS couplmg conductor- 104,416 8/1964 Norway.

References C'ted ELI LIEBERMAN, Primary Examiner UNITED STATES PATENTS 5 2,630,487 3/1953 Gurcwitsch 333-97 US. Cl. X.R. 3,386,054 5/1968 Spikula 333-21 315-39, 39.53 

